"Disable cache to (re)gain some sanity" because Chrome continues to cache things it shouldn't, including the contents of file:// URLs and in some cases, even content with headers that specify it shouldn't be cached.
mumble grumble
Cool to see some of these features finally documented, though. I had no idea you could drag-drop elements to reorder them.
For those looking to try out the (useful!) Heap Snapshot tool, please be aware that it has a bad habit of crashing tabs. It tends to happen the most when a tab is already using a lot of memory, but sometimes it just happens. So don't do it on a tab that contains any state you might want to hang onto.
One cool feature they don't mention: You can edit code in the script debugger and then hit ctrl+s to update it live in the running page. It's pretty useful for experimenting or for adding tracing points to existing code.